elvish/pkg/eval/compiler.go
2020-01-11 03:01:30 +00:00

123 lines
3.1 KiB
Go

package eval
//go:generate ./boilerplate.py
import (
"fmt"
"strings"
"github.com/elves/elvish/pkg/diag"
"github.com/elves/elvish/pkg/parse"
"github.com/elves/elvish/pkg/util"
)
// compiler maintains the set of states needed when compiling a single source
// file.
type compiler struct {
// Builtin namespace.
builtin staticNs
// Lexical namespaces.
scopes []staticNs
// Variables captured from outer scopes.
capture staticNs
// Position of what is being compiled.
begin, end int
// Information about the source.
srcMeta *Source
}
func compile(b, g staticNs, n *parse.Chunk, src *Source) (op Op, err error) {
cp := &compiler{b, []staticNs{g}, make(staticNs), 0, 0, src}
defer util.Catch(&err)
return Op{cp.chunkOp(n), src}, nil
}
func (cp *compiler) compiling(n parse.Node) {
cp.begin, cp.end = n.Range().From, n.Range().To
}
func (cp *compiler) errorpf(begin, end int, format string, args ...interface{}) {
util.Throw(NewCompilationError(fmt.Sprintf(format, args...),
*diag.NewContext(cp.srcMeta.Name, cp.srcMeta.Code, begin, end)))
}
func (cp *compiler) errorf(format string, args ...interface{}) {
cp.errorpf(cp.begin, cp.end, format, args...)
}
func (cp *compiler) thisScope() staticNs {
return cp.scopes[len(cp.scopes)-1]
}
func (cp *compiler) pushScope() staticNs {
sc := make(staticNs)
cp.scopes = append(cp.scopes, sc)
return sc
}
func (cp *compiler) popScope() {
cp.scopes[len(cp.scopes)-1] = make(staticNs)
cp.scopes = cp.scopes[:len(cp.scopes)-1]
}
func (cp *compiler) registerVariableSet(qname string) bool {
return cp.registerVariableAccess(qname, true)
}
func (cp *compiler) registerVariableGet(qname string) bool {
return cp.registerVariableAccess(qname, false)
}
func (cp *compiler) registerVariableAccess(qname string, set bool) bool {
readLocal := func(name string) bool { return cp.thisScope().has(name) }
readUpvalue := func(name string) bool {
for i := len(cp.scopes) - 2; i >= 0; i-- {
if cp.scopes[i].has(name) {
// Existing name: record capture and return.
cp.capture.set(name)
return true
}
}
return false
}
readBuiltin := func(name string) bool { return cp.builtin.has(name) }
readNonPseudo := func(name string) bool {
return readLocal(name) || readUpvalue(name) || readBuiltin(name)
}
createLocal := func(name string) bool {
if set && name != "" && !strings.ContainsRune(name[:len(name)-1], ':') {
cp.thisScope().set(name)
return true
}
return false
}
ns, name := SplitQNameNsFirst(qname) // ns = "", name = "ns:"
name1 := name // name1 = "ns:"
if name != "" && strings.ContainsRune(name[:len(name)-1], ':') {
name1, _ = SplitQNameNsFirst(name)
}
// This switch mirrors the structure of that from (*Frame).ResoleVar.
switch ns {
case "E:":
return true
case "e:":
return !set && strings.HasSuffix(name, FnSuffix)
case "local:":
return readLocal(name1) || createLocal(name)
case "up:":
return readUpvalue(name1)
case "builtin:":
return readBuiltin(name1)
case "", ":":
return readNonPseudo(name1) || createLocal(name)
default:
return readNonPseudo(ns)
}
}